Student intern

RIKEN AICS started a summer internship program in 2014. Our group accepted three internship students, Mr. Kitano from Hokkaido University (standing, middle), Mr. Kikuchi from Tohoku University (left), and Mr. Taniguchi from Hyogo Prefecture University (right). They joined us on August 29, 2014, and started working on short-term precipitation forecasts purely based on super-rapid 30-second observation data. Dr. Shigenori Otsuka, a researcher (sitting on the right), supervises their research activities. They all have different backgrounds, and I am very happy to see them discuss and help each other to tackle the tough problem. They have been making wonderful progress so far, with a lot of excitement and curiosity. I feel lucky to have this great opportunity to interact with those bright and enthusiastic young scientists.

10240-member ensemble Kalman filtering with an intermediate AGCM

We have achieved running a 3-week experiment of a 10240-member local ensemble transform Kalman filter (LETKF) with a simple low-resolution AGCM known as the SPEEDY model. The figure above shows 10240 equally-likely parallel earths, with magnified pictures. Every earth is slightly different, withing the range of uncertainties to the best of our knowledge.

The large ensemble data assimilation computations were only possible using the leading-edge K computer and the eigenvalue solver "EigenExa" that allows an extremely effective use of the K computer. We achieved amazingly high 44% efficiency, 263 TFLOPS using 4608 nodes of the K computer (about 1/20 of the full capacity). The parallel-efficient LETKF was also a must.

With 10240 members, we could obtain a very precise probabilistic representation of the earth atmosphere. Long-range error correlations beyond continental scales and bimodal structures of moisture variables were clearly represented. These were very difficult to observe with less than a few hundred members, a typical choice in ensemble data assimilation of the global atmosphere.

For more details, refer to the press release on this research achievement. Here are the links to the press release and the original research article published in Geophysical Research Letters.

• RIKEN Press Release (English, Japanese)

• Miyoshi, T., K. Kondo, and T. Imamura, 2014: The 10240-member ensemble Kalman filtering with an intermediate AGCM. Geophys. Res. Lett., 41, doi:10.1002/2014GL060863.

3rd RIKEN-Kyoto University Joint Workshop on Data Assimilation

The third workshop was held on Monday, July 28, 2014, in Kobe, following the first (blog) and the second. Four mathematicians and seven from my group on the application side discussed about mathematical problems on data assimilation. This time, my group provided several specific problems that we have been facing in our various application research.

Welcome lunch for Drs. Guo-Yuan Lien and Juan Ruiz

On Friday, July 11, 2014, we had a warm welcoming party for Drs. Guo-Yuan Lien (back row, fourth from left) and Juan Ruiz (front row, left most) over lunch in Kachoen. Our lab has been growing consistently by now, with eight full-time scientists and technical staff and three supporting staff in addition to five visiting scientists. Dr. Lien recently graduated from the University of Maryland, and his main focus was precipitation data assimilation in global numerical weather prediction. He will work on Big Data Assimilation (BDA) with the next-generation LES (large-eddy simulation) weather model SCALE. As for Dr. Ruiz, this is his third visit to Japan, and this time, he will stay for three months. He will also work on the BDA project with particular foci on the quality control of the Osaka/Kobe Phased Array Weather Radar and on parameter estimation methods in BDA applications.

Visiting Phased Array Weather Radar in Osaka University

On July 9, 2014, we have visited Professor Ushio at the Osaka University Suita Campus and had a wonderful opportunity to look at the Phased Array Weather Radar (top photo). Professor Ushio was very kind and stopped the radar operation for us to enter the radar dome to look inside. There was a large flat plate barely fitting in the dome. It rotated quite fast, 10 seconds per round. Once Professor Ushio turned on the radar again, we could find some echoes around 50-60 km away, near the maximum range of the radar. The radar image was refreshed amazingly fast, only every 30 seconds.

We are working very hard on using the data from this particular new type of radar most effectively and efficiently, and try to improve the very short-range weather forecasts through "Big Data Assimilation" innovations. Observing the actual radar that we are working on really helped enhance our motivation. What Professor Ushio was saying on TV "Yume-no-tobira" (meaning "Door to Dream") echoed over in our mind: "we just work hard, faithfully and honestly."

Weather station POTEKA II installed at AICS

On June 30, 2014, in collaboration with Meisei Electric, a surface weather station "POTEKA II" developed by Meisei Electric has been installed on the roof of the AICS building, Kobe, Japan. POTEKA II includes a barometer, thermometer, hygrometer, ultrasonic anemometer (the white thing in the middle of the picture), and rain gauge (the black thing on the right). In the picture, we can also find the Kobe Airport island (top left corner). POTEKA II measures these weather variables every 30 seconds and automatically reports to the Meisei server through a commercial mobile phone network. We have also installed the same type of weather stations at seven elementary schools in Kobe. We will investigate how these high-density, high-frequency surface weather measurements could possibly help improve the local severe weather prediction using the K computer.

MEXT Minister Prize

On April 15, 2014, I had the honor to receive the Young Scientists' Prize from the Minister of Education, Culture, Sports, Science and Technology (MEXT). This is the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology.

http://www.mext.go.jp/b_menu/houdou/26/04/1346090.htm
http://www.riken.jp/pr/topics/2014/20140415_2/